One of the benefits of using reflowable text (e.g., text that automatically wraps words to the next line as the user changes window size and thereby relocates the right margin of the page) in electronic publications is that display properties can be changed to suit a user's preferences. A common use of this control is to change the size of text when rendering the electronic publication. As the size of the text increases, words can be “forced” from the right margin to the next line.
Many electronic book (“eBook”) applications limit the number of text sizes that a user may select to a fixed number (for instance, small, medium and large), although the actual number of potential text sizes may be much greater. This is because allowing users such control over the display of content causes a dilemma for those tasked with designing content—such as content creators and content editors—to be rendered. While certain areas of content may have no issues being viewed in multiple sizes, other areas of the same content may not be as simple to change. For example, an electronic newspaper may have a complex layout to the front page. While full article pages can easily be zoomed, a complex front page with multiple stories in small boxes may become entirely unreadable when text size is changed.
For such complex layouts, prior efforts have taken two approaches. The first is to simply forbid text size changes. An example of this approach is the Portable Document Format file format, or “PDF.” Such an approach limits the usefulness of an electronic publication, by eliminating a desired feature. Producing multiple fixed-size documents to address user requirements (for instance a large print version for the visually impaired) is time-consuming, costly and creates problems for content distribution.
The other approach is to simply allow the user—the reader—full control over the content. While this approach can work, especially in an environment where the content is limited to a single “page” that can be scrolled, it does not work very well in complex layouts as all areas of a page may reflow.